Rails - Postgres - could not connect to server: Connection refused (PG::ConnectionBad)

Question

Yesterday I've install Postgres and pgAdminIII, all worked correctly, but after reload it stopped working. After rails server I've got error message:

=> Booting Thin
=> Rails 3.2.13 application starting in development on http://0.0.0.0:3000
=> Call with -d to detach
=> Ctrl-C to shutdown server
Exiting
/home/home/.rvm/gems/ruby-1.9.3-p448/gems/activerecord-3.2.13/lib/active_record/connection_adapters/postgresql_adapter.rb:1216:in `initialize': could not connect to server: Connection refused (PG::ConnectionBad)
        Is the server running on host "localhost" (127.0.0.1) and accepting
        TCP/IP connections on port 5432?
        from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/activerecord-3.2.13/lib/active_record/connection_adapters/postgresql_adapter.rb:1216:in `new'
        from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/activerecord-3.2.13/lib/active_record/connection_adapters/postgresql_adapter.rb:1216:in `connect'
        from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/activerecord-3.2.13/lib/active_record/connection_adapters/postgresql_adapter.rb:324:in `initialize'
        from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/activerecord-3.2.13/lib/active_record/connection_adapters/postgresql_adapter.rb:28:in `new'
        from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/activerecord-3.2.13/lib/active_record/connection_adapters/postgresql_adapter.rb:28:in `postgresql_connection'
        from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_pool.rb:315:in `new_connection'
        from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_pool.rb:325:in `checkout_new_connection'
        from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_pool.rb:247:in `block (2 levels) in checkout'
        from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_pool.rb:242:in `loop'
        from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_pool.rb:242:in `block in checkout'
        from /home/home/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/1.9.1/monitor.rb:211:in `mon_synchronize'
        from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_pool.rb:239:in `checkout'
        from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_pool.rb:102:in `block in connection'
        from /home/home/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/1.9.1/monitor.rb:211:in `mon_synchronize'
        from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_pool.rb:101:in `connection'
        from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_pool.rb:410:in `retrieve_connection'
        from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_specification.rb:171:in `retrieve_connection'
        from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_specification.rb:145:in `connection'
        from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/activerecord-3.2.13/lib/active_record/railtie.rb:88:in `block in <class:Railtie>'
        from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/railties-3.2.13/lib/rails/initializable.rb:30:in `instance_exec'
        from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/railties-3.2.13/lib/rails/initializable.rb:30:in `run'
        from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/railties-3.2.13/lib/rails/initializable.rb:55:in `block in run_initializers'
        from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/railties-3.2.13/lib/rails/initializable.rb:54:in `each'
        from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/railties-3.2.13/lib/rails/initializable.rb:54:in `run_initializers'
        from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/railties-3.2.13/lib/rails/application.rb:136:in `initialize!'
        from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/railties-3.2.13/lib/rails/railtie/configurable.rb:30:in `method_missing'
        from /home/home/Projects/mostdance/config/environment.rb:5:in `<top (required)>'
        from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/activesupport-3.2.13/lib/active_support/dependencies.rb:251:in `require'
        from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/activesupport-3.2.13/lib/active_support/dependencies.rb:251:in `block in require'
        from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/activesupport-3.2.13/lib/active_support/dependencies.rb:236:in `load_dependency'
        from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/activesupport-3.2.13/lib/active_support/dependencies.rb:251:in `require'
        from /home/home/Projects/mostdance/config.ru:3:in `block in <main>'
        from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/rack-1.4.5/lib/rack/builder.rb:51:in `instance_eval'
        from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/rack-1.4.5/lib/rack/builder.rb:51:in `initialize'
        from /home/home/Projects/mostdance/config.ru:in `new'
        from /home/home/Projects/mostdance/config.ru:in `<main>'
        from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/rack-1.4.5/lib/rack/builder.rb:40:in `eval'
        from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/rack-1.4.5/lib/rack/builder.rb:40:in `parse_file'
        from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/rack-1.4.5/lib/rack/server.rb:200:in `app'
        from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/railties-3.2.13/lib/rails/commands/server.rb:46:in `app'
        from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/rack-1.4.5/lib/rack/server.rb:304:in `wrapped_app'
        from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/rack-1.4.5/lib/rack/server.rb:254:in `start'
        from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/railties-3.2.13/lib/rails/commands/server.rb:70:in `start'
        from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/railties-3.2.13/lib/rails/commands.rb:55:in `block in <top (required)>'
        from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/railties-3.2.13/lib/rails/commands.rb:50:in `tap'
        from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/railties-3.2.13/lib/rails/commands.rb:50:in `<top (required)>'
        from script/rails:6:in `require'
        from script/rails:6:in `<main>'

This is my database.yml file:

development:
  host: localhost
  adapter: postgresql
  encoding: unicode
  database: mydb
  pool: 5
  timeout: 5000
  username: postgres
  password: password
  min_messages: WARNING

test:
  host: localhost
  adapter: sqlite3
  database: db/test.sqlite3
  pool: 5
  timeout: 5000

production:
  adapter: postgresql
  encoding: unicode
  database: mydb
  pool: 5
  timeout: 5000
  username: postgres
  password: password
  host: 127.0.0.1
  port: 5432
  min_messages: WARNING

Also I try to run server Postgres:

su postgres /etc/init.d/postgresql start

Password: 
 * Starting PostgreSQL 9.1 database server                                                                                                                                                       * Use of uninitialized value $info{"pgdata"} in -d at /usr/bin/pg_ctlcluster line 331.
Use of uninitialized value $info{"pgdata"} in concatenation (.) or string at /usr/bin/pg_ctlcluster line 332.
Error:  is not accessible or does not exist

Also I don't know why, but now rails server put this error:

=> Booting Thin
=> Rails 3.2.13 application starting in development on http://0.0.0.0:3000
=> Call with -d to detach
=> Ctrl-C to shutdown server
Exiting
/home/home/.rvm/gems/ruby-1.9.3-p448/gems/activerecord-3.2.13/lib/active_record/connection_adapters/postgresql_adapter.rb:1216:in `initialize': FATAL:  Peer authentication failed for user "postgres" (PG::ConnectionBad)

Please, help me! If you need more information - write into comments and I will update my question

Answer 1

When I have had this issue in the past there are often a few things I can do to get it running, most of them seem simple, but I'm mighty forgetful --

sometimes I haven't actually created the DB after switching to postgres

bundle exec rake db:create

and then get all of my tables in there --

bundle exec rake db:migrate

other times I need to double check and make sure the PG gem is installed

gem install pg

Answer 2

If you are on Mac. then try reinstalling Postgresapp and then restarting everything. Make sure to import the database again.

If you are on Linux the reinstall Postgres and then restart everything.